The present invention related generally to routing optical fiber in electronic equipment and more particularly to an optical fiber harness for measurement test equipment.
Optical components are used in measurement test equipment, such as optical time domain reflectometers (OTDR), optical spectrum analyzers, oscilloscopes and the like, for generating and receiving optical signals to and from a device under test. Generally, the optical components are manufactured with a length of optical fiber extending from the component that allow coupling to another component. The layout of optical and electrical components on a circuit board of the measurement instrument may result in an excess length of optical fiber between optical components. This requires the optical fiber to be affixed to the circuit board in a manner that does not produce tight bends or kinks in the fiber. A common solution is to place routing clips on the circuit board that accept the optical fiber. One type of routing clip is the Micro Wire Saddle, manufactured and sold by Richco, Inc., Chicago, Ill. under part number MWS-1-01. The micro wire saddle has a narrow rectangular base with sidewalls extending upward from the ends of the base. Extending inward from the top of the sidewalls are downward angled overlapping fingers having a small gap at the ends of the fingers. Extending downward from the bottom of the base is a snap-lock retention member that engage holes formed in the circuit board. Another type of routing clip manufactured by the same company is the Micro Wire Saddle on Base, sold under part numbers MWSB-1-01A-RT and MWSEB. Each micro saddle on base are of similar construction with a square base and opposing narrow sidewalls extending upward from two sides of the base. Extending inward from the top of the sidewalls are downward angled overlapping fingers having a small gap at the ends of the fingers. The underside of the base has double sided adhesive tape. The adhesive side micro wire saddle on base is secured to open spaced laid out on the circuit board. Excess optical fiber is routed through the routing clips.
A drawback to using these types of routing clips is that they take-up valuable real estate on the circuit board that could be used for instrument components. Additionally, board layout complicated in the fact that routing clip locations have to be provided on the board that correspond to the excess amount of fiber on the optical component. Further, care must be used in routing the fiber through the routing clips to make sure that no kinks or type bends are formed in the optical fiber.
What is needed is a an optical fiber harness that does not take-up real estate on the circuit board. The optical fiber harness should be easily placable on the circuit board and easily receive an optical fiber. The optical fiber harness should also provide a constant bend radius for the optical fiber.
Accordingly, the present invention is an optical fiber harness having a flat, flexible unitary plastic body folded to form first and second segments. Each segment has a free end and a common fold junction. The first segment is formed into a substantially circular member having outwardly extending tabs. Each tab has an aperture formed therein for receiving an optical fiber. Each tab may be formed with a notch that intersects the apertures for placement of an optical fiber in the notch. A locking member is formed at the free end of the first segment for securing the free end of the circular member to the other end of the circular member at the common fold junction. The second segment is formed into a straight member extending from the common fold junction and intersecting the circular member forming a chord through the circular member. The straight portion has at least a first attachment member extending past the circular member for securing the optical fiber harness onto a circuit board and a locking member for securing the free end of the straight member to the circular member.
In one embodiment, the free end of the second segment extends past the circular member and the attachment member comprises an aperture formed in the straight member at the free end of the second segment. In a further embodiment, the attachment member extends past the circular member at the common folded junction and comprise a notch formed in the attachment member adapted for receiving a coaxial cable. Both attachment member embodiments may be incorporated into the optical fiber harness. The first segment locking member has a hook-like projection formed in the free end of the first segment that engages a notched portion of the first segment adjacent to the common fold junction. The second segment locking member has a first notch formed in the straight member for receiving the intersecting portion of the circular member and a second notch formed in the intersecting circular member for receiving the straight member.
The objects, advantages and novel features of the present invention are apparent from the following detailed description when read in conjunction with the appended claims and attached drawings.